This invention relates generally to devices and methods for shaping tissue by deploying one or more devices in body lumens adjacent to the tissue. One particular application of the invention relates to a treatment for mitral valve regurgitation through deployment of a tissue shaping device in the patient's coronary sinus or great cardiac vein.
The mitral valve is a portion of the heart that is located between the chambers of the left atrium and the left ventricle. When the left ventricle contracts to pump blood throughout the body, the mitral valve closes to prevent the blood being pumped back into the left atrium. In some patients, whether due to genetic malformation, disease or injury, the mitral valve fails to close properly causing a condition known as regurgitation, whereby blood is pumped into the atrium upon each contraction of the heart muscle. Regurgitation is a serious, often rapidly deteriorating, condition that reduces circulatory efficiency and must be corrected.
Two of the more common techniques for restoring the function of a damaged mitral valve are to surgically replace the valve with a mechanical valve or to suture a flexible ring around the valve to support it. Each of these procedures is highly invasive because access to the heart is obtained through an opening in the patient's chest. Patients with mitral valve regurgitation are often relatively frail thereby increasing the risks associated with such an operation.
One less invasive approach for aiding the closure of the mitral valve involves the placement of a tissue shaping device in the cardiac sinus, a vessel that passes adjacent the mitral valve annulus. (As used herein, “coronary sinus” refers to not only the coronary sinus itself, but also to the venous system associated with the coronary sinus, including the great cardiac vein.) The tissue shaping device is designed to reshape the vessel and surrounding valve tissue to reshape the valve annulus and other components, thereby promoting valve leaflet coaptation. This technique has the advantage over other methods of mitral valve repair because it can be performed percutaneously without opening the chest wall. Examples of such devices are shown in U.S. patent application Ser. No. 10/142,637, “Body Lumen Device Anchor, Device and Assembly” filed May 8, 2002; U.S. patent application Ser. No. 10/331,143, “System and Method to Effect the Mitral Valve Annulus of a Heart” filed Dec. 26, 2002; U.S. patent application Ser. No. 10/429,172, “Device and Method for Modifying the Shape of a Body Organ,” filed May 2, 2003; and U.S. application Ser. No. 10/742,600 filed Dec. 19, 2003.